The use of sensors in body lumens is well known. For example, U.S. Pat. No. 4,485,813 describes a sensor that can be permanently implanted in a specific location within the human body in an implantable medical device such as a pacemaker. In other applications sensors are implanted alone in a body lumen. U.S. Pat. Nos. 6,645,143, 6,053,873, 6,442,413 and United States Publication Serial No. 2002/0188207 describe medical monitoring sensors designed to be implanted in the vascular system and are capable of sensing and transmitting via a telemetry link to an external monitor.
The implanted sensors are utilized for monitoring physical, chemical or physiological parameters in the body. The aim of such sensors is to accurately monitor the desired parameter.
The position of the sensor within the lumen can influence the accuracy of the measurement. Positioning of a sensor facing a lumen wall can alter the sensing ability. Furthermore, positioning of a sensor pressing against the lumen wall in blood vessels may encourage responses, such as neo-intimal growth, which can influence and/or impact the long and short term accuracy of measurements.
United States Publication Serial No. 2002/0188207 discloses a device and method for anchoring a sensor at the center of the lumen. This concept addresses the issue of tissue growth. However, it is problematic to axially align multiple sensors in the same vicinity of a lumen, since a first sensor would block the further sensor(s) from blood flow through the lumen. Thus, it is desirable, and often functionally necessary, to radially and/or circumferentially off-set the sensors of a multiple sensor arrangement, so that they are not coaxially aligned. On the other hand, it is desirable, and often functionally necessary, to operably connect the individual sensors of a multiple sensor arrangement.
There are several medical procedures that require insertion of catheters or other devices through a body lumen and especially through the vascular system, for example, Swan-Ganz catheter to the pulmonary artery for monitoring hemodynamic parameters. Thus, a sensor implantation device should not prevent accessibility to a desired location within the vascular system.